The White House has called for Beijing to take action to stop computer attacks aimed at stealing company secrets. Hundreds of cyberattacks have been traced to China, and a security firm said last month that it found a wave of attacks on 140 companies that originated in a building in Shanghai housing a military unit.

‘‘This is a very serious threat to our economic interests,’’ Lew told reporters. “There was no mistaking how seriously we take this issue.’’

Chinese officials have denied their government is involved and say China also is a victim of cyberattacks.

In talks with Chinese leaders, Lew emphasized that Washington sees a distinction between criminal cyberattacks and spying by state-sponsored enterprises, said an American official who spoke on condition of anonymity in order to brief reporters. The official declined to say how Chinese officials responded.

On North Korea, Washington wants Beijing to use its status as the North’s main source of trade and aid to press Pyongyang to discard its nuclear program.

‘‘We made clear that the US views the provocative actions of North Korea as very serious, and we will continue to pursue methods available to change the policy perspective in Pyongyang,’’ Lew said. ‘‘We share a common objective of a denuclearized Korean Peninsula, and we will continue to discuss it.’’

However, asked whether Washington was considering sanctions that might affect Chinese banks, Lew said US leaders want to avoid imposing burdens on the Chinese economy.